Linear curve to wave curve
Press Z to work in wireframe view


Enable Add mesh: extra objects with File -> User preferences -> Add-on


Generate linear to wave, with Add -> Mesh -> math function -> XYZmath surface and make sure you leave 'U wrap' blank:

Add a mirror modifier and enable the highlighted button:

Press Tab tp enter Edit mode and move the waves from each other:

Add a circle curve:

Then select the wave and add a curve modifier

Scale the circle curve:

Scale everythong with -1 along the x-axis and rotate to obtain: